Which one among the following is the largest monkey ?

Among the options provided, the Baboon is the largest monkey. Taxonomically, primates are divided into monkeys and apes. Apes, such as the Gorilla, are characterized by the absence of a tail and generally larger body sizes [t2, t3]. Gorillas are classified as 'Great Apes' rather than monkeys [t4, t7]. Monkeys are further divided into Old World and New World groups. Baboons are Old World monkeys (genus Papio) known for their customary large size and non-prehensile tails [t2]. While some monkeys can weigh over 100 pounds, the Baboon significantly outweighs New World species like the Howler monkey and Spider monkey [t2, t5]. Specifically, the Mandrill (often grouped with baboons) is the largest monkey species, followed by various baboon species. Since Gorillas are apes, the Baboon remains the largest monkey on this list.